COLQ and ARHGAP15 are Associated with Diverticular Disease and are Expressed in the Colon.

BACKGROUND: Diverticular disease is a common but poorly understood disease of the gastrointestinal tract. Recent studies have identified several single nucleotide polymorphisms (SNPs) that are associated with diverticular disease. MATERIALS AND METHODS: The genotypes of three SNPs (rs4662344 in ARHGAP15, rs7609897 in COLQ, and rs67153654 in FAM155A) were identified by Taqman assay in 204 patients with diverticular disease. Clinical characteristics were obtained from the medical record to study association with genotype. To evaluate gene expression in colon tissue, qPCR was performed on 24 patients with diverticulitis, and COLQ was localized using immunohistochemistry. RESULTS: The ARHGAP15 and COLQ SNPs were significantly associated with both diverticular disease and specifically diverticulitis, while the FAM155A was not associated with either. No association was found with clinical disease characteristics. Heterozygous genotypes at the ARHGAP15 SNP was associated with lower ARHGAP15 expression in colon tissues. COLQ protein localized to the myenteric plexus in the colon. CONCLUSIONS: This study confirmed association of the ARHGAP15 and COLQ SNPs with diverticular disease in our patients but could not confirm FAM155A SNP association. Neither of these SNPs appeared to associate with more severe disease, but genotype at the ARHGAP15 SNP did impact expression of ARHGAP15 in the colon. Additionally, this study is the first to localize COLQ in the colon. Its presence in the myenteric nervous system suggests COLQ SNP variants may contribute to diverticular disease by altering motility.

Clinical and Genetic Factors Impact Time to Surgical Recurrence After Ileocolectomy for Crohn's Disease.

OBJECTIVE: The aim of this study was to evaluate factors associated with time to surgical recurrence after Crohn's ileocolectomy. SUMMARY BACKGROUND DATA: The most common surgery performed for Crohn's disease is ileocolectomy. Identifying patients at high risk for surgical recurrence may assist with medical and surgical decision-making. METHODS: Data were obtained from 409 patients with Crohn's disease (CD) who had undergone ≥1 ileocolectomies at Penn State Hershey Medical Center. Six single-nucleotide polymorphisms (SNPs) associated with CD were evaluated in these patients: rs2076756, rs2066844, and rs2066845 in NOD2, rs4958847 and rs13361189 in IRGM, and rs2241880 in ATG16L1. Genotype and clinical factors were analyzed to determine associations with time to recurrent ileocolectomy. A subgroup analysis was performed on 241 patients naïve to biologics before initial ileocolectomy to assess the effect of biologic therapy on time to recurrent surgery. RESULTS: There were 286 patients who underwent a single ileocolectomy, whereas 123 required multiple ileocolectomies. Ileocolonic involvement [hazard ratio (HR) 1.90, 95% confidence interval (CI) 1.21-3.00, P = 0.006] and rs2066844 in NOD2 (HR 1.8, 95% CI 1.17-2.77, P = 0.007) were associated with decreased time to surgical recurrence by multivariate analysis. In patients naïve to preoperative biologics, the initiation of postoperative biologics was associated with a 40% decreased incidence of surgical recurrence (HR 0.60, CI 0.39-0.93, P = 0.02) over time. CONCLUSIONS: Ileocolonic distribution of disease and the rs2066844 SNP in NOD2 are associated with shorter time to recurrent ileocolectomy. The initiation of postoperative biologics in naïve patients was associated with a reduced incidence of recurrence over time.

Clinical and Genetic Factors Associated With Complications After Crohn's Ileocolectomy.

BACKGROUND: Ileocolectomy is the most common surgery performed for Crohn's disease, and postoperative complications occur frequently. There has been minimal evaluation of complications after ileocolectomy as a function of both clinical and genetic factors. OBJECTIVE: The purpose of this study was to evaluate both genetic and clinical factors associated with complications after Crohn's ileocolectomy. DESIGN: This was a retrospective clinical and genetic cohort study. SETTINGS: This study was conducted at a high-volume tertiary care center. PATIENTS: We identified 269 patients with Crohn's disease who had undergone 287 ileocolectomies at our institution between July 2008 and October 2018. MAIN OUTCOME MEASURES: We measured the association of complications with a combination of clinical factors and 6 Crohn's-associated single nucleotide polymorphisms in NOD2 (rs2076756, rs2066844, and rs2066845), IRGM (rs4958847 and rs13361189), and ATG16L1 (rs2241880). RESULTS: There were 86 ileocolectomies of 287 (30%) with complications requiring intervention. The single nucleotide polymorphism rs13361189 in the gene IRGM was significantly associated with complications on univariate and multivariate analysis. There were 61 patients with a variant at the rs13361189 single nucleotide polymorphism and 26 of them had complications, although only 55 of the 208 wild-type patients had complications (43% vs 26%; OR = 2.1; p = 0.02). Other significant factors associated with complication after ileocolectomy were open surgery, placement of a proximal ileostomy, and a greater perioperative decrease in hematocrit. LIMITATIONS: This study was limited by its retrospective design and inherent selection bias. CONCLUSIONS: In addition to clinical risk factors, the rs13361189 single nucleotide polymorphism in the IRGM gene was independently associated with complications after ileocolectomy for Crohn's disease. The use of such genetic determinants may identify patients at increased risk for surgical complications after ileocolectomy. See Video Abstract at http://links.lww.com/DCR/B124. FACTORES CLÍNICOS Y GENÉTICOS ASOCIADOS CON COMPLICACIONES DESPUÉS DE LA ILEOCOLECTOMÍA DE CROHN: La ileocolectomía es la cirugía más común realizada para la enfermedad de Crohn y con frecuencia ocurren complicaciones postoperatorias. Ha habido una evaluación mínima de complicaciones después de la ileocolectomía, en función de factores clínicos y genéticos.Evaluar factores genéticos y clínicos asociados con complicaciones, después de la ileocolectomía por Crohn.Estudio retrospectivo de cohorte clínico y genético.Este estudio se realizó en un centro de atención terciaria de alto volumen.Identificamos a 269 pacientes con enfermedad de Crohn, sometidos a 287 ileocolectomías en nuestra institución, entre julio de 2008 y octubre de 2018.La asociación de complicaciones con una combinación de factores clínicos y seis polimorfismos de un solo nucleótido asociados a Crohn en NOD2 (rs2076756, rs2066844 y rs2066845), IRGM (rs4958847 y rs13361189) y ATG16L1 (rs2241880).Hubieron 86 ileocolectomías en 287 (30%) pacientes con complicaciones que requirieron intervención. El polimorfismo de un solo nucleótido rs13361189 en el gen IRGM se asoció significativamente con complicaciones en el análisis univariado y multivariado. Hubieron 61 pacientes con una variante en el polimorfismo de un solo nucleótido rs13361189 y 26 de ellos tuvieron complicaciones, mientras que solo 55 de los 208 pacientes de tipo salvaje (WT) tuvieron complicaciones (43% vs 26%, OR 2.1, p = 0.02). Otros factores significativos asociados con las complicaciones después de la ileocolectomía fueron, la cirugía abierta, la colocación de una ileostomía proximal y una mayor disminución perioperatoria del hematocrito.Este estudio estuvo limitado por su diseño retrospectivo y sesgo de selección inherente.Además de los factores de riesgo clínicos, el polimorfismo de un solo nucleótido rs13361189 en el gen IRGM se asoció independientemente con complicaciones después de la ileocolectomía, para la enfermedad de Crohn. El uso de tales determinantes genéticos puede identificar a los pacientes con mayor riesgo de complicaciones quirúrgicas, después de la ileocolectomía. Consulte Video Resumen en http://links.lww.com/DCR/B124.

Ulcerative colitis neoplasia is not associated with common inflammatory bowel disease single-nucleotide polymorphisms.

BACKGROUND: Neoplasia complicating ulcerative colitis (UC-neoplasia) is a problem that is poorly addressed by present surveillance techniques. The association of greater than 300 single nucleotide polymorphisms (SNPs) with inflammatory bowel disease (IBD) suggests the possibility that certain genetic polymorphisms might identify patients with UC destined for malignant degeneration. This present study tested the hypothesis that presently known IBD-associated SNPs may correlate with UC-neoplasia. MATERIALS AND METHODS: A total of 41 patients with UC-neoplasia (mean age 56 ± 2.1 years) were identified from our divisional IBD Biobank (low-grade dysplasia n = 13, high-grade dysplasia n = 8, colorectal cancer [CRC] n = 20). These patients were individually age, sex, and disease duration matched with UC patients without neoplasia. Primary sclerosing cholangitis and family history of CRC were recorded. Patients were genotyped for 314 of the most commonly IBD-associated SNPs by a custom SNP microarray. Logistic regression and Fischer exact test were used for statistical analysis. RESULTS: After Bonferroni correction, none of the 314 IBD-associated SNPs correlated with UC-neoplasia when compared with matched UC controls. The incidence of primary sclerosing cholangitis was greater in the UC-neoplasia group (10/41, 24% vs 3/41, 7%; P = .03) compared with UC controls. The severity of neoplasia (low grade dysplasia versus high grade dysplasia versus CRC) correlated with disease duration (7.9 vs 13.4 vs 20.7 years, respectively). CONCLUSION: The lack of correlation between well-known IBD-associated SNPs and UC-neoplasia demonstrated in this study suggests that the development of neoplasia in patients with UC is associated with genetic determinants other than those that predispose to inflammation or results from posttranslational modifications or epigenetic factors rather than germline polymorphisms.

T-cell activation Rho GTPase-activating protein expression varies with inflammation location and severity in Crohn's disease.

BACKGROUND: The T-cell activation Rho GTPase-activating protein (TAGAP) gene has a regulatory role in T cell activation. We have previously suggested a correlation between the TAGAP-associated single nucleotide polymorphism rs212388 and protection from anal sepsis in Crohn's disease (CD) patients. The present study sought to evaluate TAGAP's expression in colonic tissue of CD patients with varying disease severity and location. MATERIALS AND METHODS: Five transverse, 17 left, and five sigmoid colectomy specimens from 27 CD patients with varying disease severity (16 male, mean age at diagnosis 26.4 ± 2.2 y) were evaluated for TAGAP messenger RNA expression. Fisher exact, Mann-Whitney, and Welch two-sample t-tests were used for statistical evaluation. Immunohistochemistry confirmed results. RESULTS: Patients with tissue demonstrating lower TAGAP messenger RNA expression (less than the overall mean) were younger at diagnosis (mean age 21.1 ± 6.3 versus 32.5 ± 13 y, P = 0.009). Increased TAGAP expression was seen in moderate or severely diseased tissue versus tissue with no or mild disease (RQ = 1.3 ± 0.34 versus 0.53 ± 0.09, P = 0.050). This was the most dramatic in the sigmoid colon (P = 0.041). TAGAP expression was increased in more distal tissue with a significant difference seen when comparing transverse versus sigmoid colon with moderate or severe disease (0.51 ± 0.14 versus 1.9 ± 0.37, P = 0.049). CONCLUSIONS: Colonic expression of TAGAP in CD patients varied according to disease severity and location, being the most elevated in patients with severe disease in the sigmoid colon. Whether changes in TAGAP expression are a result of disease response or inherent to the disease pathophysiology itself remains to be determined. This gene warrants further investigation for its role in CD.